Transcript Principles and Practices of Biosafety

Animals and Allergens
Risk Assessment for Work with
Research Animals
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Risks associated with the research agent used in
the animal
 chemical, physical, biological
Risks associated with the species of animal used
 zoonotic agents
Risks associated with animal maintenance
 ergonomic factors, bites, scratches, allergens
Risks Associated with the Agent
Used
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Chemical agents
 carcinogens, mutagens
 toxic chemicals
 anesthetics
Physical agents
 radiation
 heat
 sound
Risks Associated with the Agent
Used
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Potentially biohazardous agents
 deliberate use of an infectious agent in
animals for research purposes
 maintenance of infected animal for
duration of experiment
 sacrifice, necropsy and harvesting of
agent or infected tissue
Transmission of Biohazards
During Work with Animals
Airborne
 Release of infectious aerosols by animal by
sneezing, coughing
 Release during nasal infection or aerosol
challenge
 Aerosolization from bedding and excreta
 During surgical procedures
 During birthing
Transmission of Biohazards
During Work with Animals
Direct Inoculation
 Needlesticks during injection/inoculation
process
 Bites and scratches from infected animal
Transmission of Biohazards
During Work with Animals
Direct exposure of mucous membranes
(by splash or splatter)
 During surgical procedures
 During injection
 During necropsy
Transmission of Biohazards
During Work with Animals
Indirect transmission and ingestion
 From contaminated hands or gloves to mouth
 Facial contamination directly from animal
 Transfer of parasites by animal handling
Indirect transmission with eye or mucous
membrane exposure
 Dust from bedding
 Splash during cage washing
 “Dirty” environment
Risk Reduction: Containment of
Infectious Agent
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Containment must include:
 Primary containment
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Enclosed filtered caging system
Biosafety cabinets
Safety equipment
PPE
Secondary containment
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The containment facility
• Negative pressurization
• Nonrecirculated air supply
• Ventilation must consider wellbeing of animal
Containment Caging Systems
No Containment
 Open (standard) cage
 Some Containment
 Filter top cage
(microisolator cage)
 Full Containment
 Fully enclosed in
ventilated rack
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Containment Caging Systems
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Microisolator Cage
works like a Petri dish
 open gaps around lid edge allow limited air
exchange
 may lead to more labor intensive husbandry due
to moisture and ammonia buildup
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Containment Caging Systems
Individual cages sealed into rack with
supplied air under negative pressure
 Both supply and exhaust usually HEPA
filtered
 Ventilation must control humidity and
buildup of ammonia
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Containment Caging Systems
Can install cages in class III biosafety
cabinet
 Cages are completely contained with glove
port access
 Very motion-limiting
 Transfer in and out may be an issue
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Containment Caging Systems
BioBubble (Ft. Collins, CO) makes softwall ventilated enclosures
 Can be containment or barrier style
 Large equipment can be surface-mounted in
wall
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Special Animal Housing Situations
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Barrier colonies
 Special breeds - often immunocompromised,
“fragile”, expensive (SCID-Hu, nude athymics)
 Transgenics - often even more fragile and
expensive (knockouts, microinjected, combos)
 Specific pathogen-free (SPF) - bred and raised
to be missing certain specific microorganisms
Isolation colonies
 Extensive SPFs and defined flora animals
 Gnotobiotes (an entirely different animal!)
Zoonoses
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Zoonotic disease: A disease of animals that
can be transmitted under natural conditions
and cause disease in humans
 Wild caught animals most hazardous
 Random source animals (e.g., from a
pound) are also a risk
 Purpose bred animals pose least risk
Some Animals and Their
Zoonoses
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Animal
Macaque monkeys
Sheep
White mouse
Dogs, cats, skunks,
raccoons, bats
Cattle, NHP
Cats
Parrots, macaws
Chickens
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Disease
Herpes B virus
Q fever
Hantavirus
Rabies
Tuberculosis
Toxoplasmosis
Psittacosis
Avian influenza
Rodent Zoonoses
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Rat bite fever (Streptobacillus moniliformis,
Spirillum minus)
 transmission: direct contact (bites)
Lymphocytic choriomeningitis (LCM, a virus)
 transmission: inhalation
Leptospirosis (Leptospira spp.)
 transmission: inhalation
Others include ringworm (fungal), scabies (mites,
an ectoparasite)
Transmission of Zoonoses
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Enteric route (fecal/oral)
 Salmonella, Shigella, Campylobacter,
Giardia, Toxoplasma, Cryptosporidium,
Entamoeba, Hepatitis A
Respiratory route
 Q fever, Chlamydia, Measles
Skin contact
 Ringworm (Tinea), Measles, Monkeypox
Control of Zoonoses
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Get information on
species and agent
Quarantine animals prior
to use
Use Engineering controls
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written SOPs and
manuals
Use PPE
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facility construction and
secondary barriers
Consider the need for
containment caging
Use Administrative
controls
additional protection for
worker
Practice good facility and
personal hygiene
Provide staff training
Laboratory Acquired Allergies
(LAA)
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Significant occupational disease
Affects >30% of all personnel working with
animals
No minimum safe exposure levels to allergens
have been established
Animal allergens found in hair, dander, urine,
saliva, serum
 fel-d-l cat allergen (in saliva and thus on skin)
is one of the strongest allergens known for
humans
Sources of Exposure to LAA
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Hair and dander shed
from animal
Urine and feces dried
in bedding
Particulates shed from
bedding material
Animal saliva
Routes of Exposure to LAA
Inhalation of airborne allergens
 during cage changing
 during animal handling
 Skin or eye contact
 usually indirect by touching skin, eyes
 Percutaneous exposure
 animal bites (saliva)
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Risk Factors for Development of
LAA
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Exposure to allergens
 duration
 frequency
 intensity
Previous allergic conditions
Other predisposing conditions
 illness
 Immunocompromised
 pets
LAA: Exposure Control
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Engineering Controls
 enclosure
 dilution ventilation
Administrative Controls
 reduce time with animals
 reduce density of animals
 housekeeping practices
Personal Protective Equipment
 respirators and clothing
Medical Surveillance